1. Field of the Invention
The present invention relates to an air-conditioning grille provided in automobiles or the like.
2. Description of the Prior Art
In general, the air-conditioning grille disclosed in Japanese Laid-Open Utility Model Publication No. 51-2849 has been well known as one mainly provided on the instrumental panel of an automobile. In this air-conditioning grille, plural wind deflecting plates made of leaf springs are fitted in a case while deformed in an arc shape. The wind deflecting plates are connected to an operation lever via a linkage composed of plural connecting members.
The operation lever gives pressure to said wind deflection plates via the linkage and their deformation states are adjusted, so that the blowing direction of the wind introduced into the case is altered.
Moreover, there is another in which slits of V shapes in cross-sectional view are formed on both right and left sides of each of the above wind deflecting plates in a constant interval, so that the wind deflecting plates are more likely to be bent (Japanese Laid-Open Utility Model Publication No. 51-6643).
In the above conventional air-conditioning grille, however, a considerable amount of operation force is required to change the wind direction by bending the wind deflecting plates by means of the operation lever due to the arrangement of the operation lever and to the elasticity of the wind deflecting plates. When the wind deflecting plates are bent, there is a problem that twist and distortion occur on the wind deflecting plates due to their own elasticity. In this case, there occur problems that the stream of the wind is disturbed to generate vortexes and to make the alternation of the wind direction incomplete. Especially, the above problems outstandingly occur in use of the wind deflecting plates with the slits.
Moreover, if the strength and rigidity of each member and the precision of bearing portions of the wind deflecting plates or the like improve in order to solve the above problems, there occurs another problem that the weight or production cost of the whole air-conditioning grille increases.
In the above air-conditioning grille, the whole wind deflecting plates are formed of the leaf springs, so that they are not likely to be bent smoothly along predetermined arcs. Therefore, air introduction edges of the wind deflecting plates are not arranged on the same alignment of the air introduction direction, so that there is a problem that noises occur especially when the strong wind is to be blown.
Furthermore, the operation lever is connected to each of the wind deflecting plates via the linkage, so that the operation force is not evenly applied to each of the wind deflecting plates. Accordingly, the above described twists or the like are generated.
Moreover, on altering the wind direction, the operation lever has to be operated against frictional force at the bearing portions of the wind deflection plates and against their own elasticity. Therefore, not only a large operational force is required, but also the operational force increases as the bending degree of the wind deflecting plates increases.
On the other hand, if the frictional force at said bearing portions is not determined appropriately, namely if it is too small, the wind deflecting plates can not be retained at a certain position when the bending degree of the wind deflecting plates increases. It is difficult to design one meeting the above contradictory requirements.